<?php 
/** 
 * 验证码类
 * @package Libraries
 * @author 江羿平<jyp@cjkt.com>
 */
namespace Libraries;
class ValidationCode {
 
  /**
   * 图片宽度
   * @var integer
   */
  public $width = 80;

  /**
   * 图片高度
   * @var integer
   */
  public $height = 30;

  /**
   * 验证码字符数
   * @var integer
   */
  public $codeNum = 4;

  /**
   * 验证码
   * @var string
   */
  public $checkCode;

  /**
   * 图像资源
   * @var resource
   */
  private $image;   //图像资源

  /**
   * 像素点数量
   * @var integer
   */
  private $disturbColorNum;
  
  /**
   * Constructor - 设置验证码参数
   * @return void
   */
  function __construct($width = 80, $height = 30, $codeNum = 4){
 
    $this->width=$width;
    $this->height=$height;
    $this->codeNum=$codeNum;
    $this->checkCode=$this->createCheckCode();

    $number=floor($width*$height/15);
    
    if($number > 240-$codeNum){
      $this->disturbColorNum= 240-$codeNum;
    }else{
      $this->disturbColorNum=$number;
    }

    $this->showImage(); 
  }

  /**
   * 生成图片验证码
   */
  public function showImage($fontFace=""){
    //第一步：创建图像背景
    $this->createImage();
    //第二步：设置干扰元素
    $this->setDisturbColor();
    //第三步：向图像中随机画出文本
    $this->outputText($fontFace);
    //第四步：输出图像
    $this->outputImage();
  }
  
  /**
   * 获取验证码字符串
   * @return string
   */
  public function getCheckCode(){
    return $this->checkCode;
  }
  
  /**
   * 创建图像
   */
  private function createImage(){
     //创建图像资源
     $this->image=imagecreatetruecolor($this->width, $this->height);
     //随机背景色
     $backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));
     //为背景添充颜色
     imagefill($this->image, 0, 0, $backColor);
     //设置边框颜色
     $border=imagecolorallocate($this->image, 0, 0, 0);
     //画出矩形边框
     imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border);
  }

  /**
   * 设置干扰元素
   */
  private function  setDisturbColor(){
   for($i=0; $i<$this->disturbColorNum; $i++){
    $color=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));
    imagesetpixel($this->image, rand(1, $this->width-2), rand(1, $this->height-2), $color);
   }
   for($i=0; $i<10; $i++){
    $color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));
    imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55, 44, $color);
   }
  }

  /**
   * 生成随机码
   * @return string
   */
  private function createCheckCode(){
    $code="23456789ABCDEFGHJKMNPQRSTUVWXYZ";
    $string='';
    for($i=0; $i < $this->codeNum; $i++){
      $char=$code{rand(0, strlen($code)-1)};
      $string.=$char;
    }
    return $string;  
  }

  /**
   * 向图像中随机画出文本
   */
  private function outputText($fontFace=""){
    for($i=0; $i<$this->codeNum; $i++){
        $fontcolor=imagecolorallocate($this->image, rand(0, 128), rand(0, 128), rand(0, 128));
        if($fontFace==""){
            $fontsize=rand(3, 5);
            $x=floor($this->width/$this->codeNum)*$i+3;
            $y=rand(0, $this->height-15);
            imagechar($this->image,$fontsize, $x, $y, $this->checkCode{$i},$fontcolor);
        }else{
            $fontsize=rand(12, 16);
            $x=floor(($this->width-8)/$this->codeNum)*$i+8;
            $y=rand($fontSize+5, $this->height);
            imagettftext($this->image,$fontsize,rand(-30, 30),$x,$y ,$fontcolor, $fontFace, $this->checkCode{$i});
        }
    }
  }

  /**
   * 输出图像
   */  
  private function outputImage() {
    if(imagetypes() & IMG_GIF){
      header("Content-Type:image/gif");
      imagepng($this->image);
    }else if(imagetypes() & IMG_JPG){
      header("Content-Type:image/jpeg");
      imagepng($this->image);
    }else if(imagetypes() & IMG_PNG){
      header("Content-Type:image/png");
      imagepng($this->image);
    }else if(imagetypes() & IMG_WBMP){
      header("Content-Type:image/vnd.wap.wbmp");
      imagepng($this->image);
    }else{
      die("PHP不支持图像创建");
    }
  }

  /**
   * Destructor - 释放图片资源
   * @return void
   */
  function __destruct(){
    imagedestroy($this->image);
  }

}
?>